Hum. Reprod. Advance Access published online on August 26, 2005
Human Reproduction, doi:10.1093/humrep/dei282
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Reproductive Medicine Unit, Department of Gynecology and Obstetrics, CHUV, 1011 Lausanne, Switzerland
* To whom correspondence should be addressed. BACKGROUND: As embryo selection is not allowed by law in Switzerland, we need a single early scoring system to identify zygotes with high implantation potential and to select zygotes for fresh transfer or cryopreservation. The underlying aim is to maximize the cumulated pregnancy rate while limiting the number of multiple pregnancies. METHODS: In all, 613 fresh and 617 frozen-thawed zygotes were scored for proximity, orientation and centring of the pronuclei, cytoplasmic halo, and number and polarization of the nucleolar precursor bodies. From these individual scores, a cumulated pronuclear score (CPNS) was calculated. Correlation between CPNS and implantation was examined and compared between fresh and frozen-thawed zygotes. The effect of freezing on CPNS was also investigated. RESULTS: CPNS was positively associated with embryo implantation in both fresh and frozen zygotes. With similar CPNS, frozen zygotes presented implantation rates as high as those of fresh zygotes. Nucleolar precursor bodies pattern and cytoplasmic halo appeared as the most important factors predictive of implantation for both types of zygotes, while pronuclei position was specifically relevant for frozen-thawed zygotes. Freezing induced an alteration of most zygote parameters, resulting in a significantly lower CPNS and a lower pregnancy rate. CONCLUSIONS: CPNS may be used as a single prognostic tool for implantation of both fresh and frozen-thawed zygotes. Lower CPNS values of frozen-thawed zygotes may also be indicative of freezing damage to zygotes. Successful implantation of frozen zygotes despite lower CPNS suggests that they may recover after thawing and in vitro culture.
Received April 1, 2005
Revised June 10, 2005
Accepted July 21, 2005
Article
Morphological scoring of human pronuclear zygotes for prediction of pregnancy outcome
Alfred Senn, E-mail: Alfred.senn{at}cpma.ch
Abstract 
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  A. Beuchat, P. Thevenaz, M. Unser, T. Ebner, A. Senn, F. Urner, M. Germond, and C.O.S. Sorzano Quantitative morphometrical characterization of human pronuclear zygotes Hum. Reprod., September 1, 2008; 23(9): 1983 - 1992. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. Isachenko, P. Todorov, Y. Dimitrov, and E. Isachenko Integrity rate of pronuclei after cryopreservation of pronuclear-zygotes as a criteria for subsequent embryo development and pregnancy Hum. Reprod., April 1, 2008; 23(4): 819 - 826. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Guerif, A. Le Gouge, B. Giraudeau, J. Poindron, R. Bidault, O. Gasnier, and D. Royere Limited value of morphological assessment at days 1 and 2 to predict blastocyst development potential: A prospective study based on 4042 embryos Hum. Reprod., July 1, 2007; 22(7): 1973 - 1981. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Donoso, C. Staessen, B.C.J.M. Fauser, and P. Devroey Current value of preimplantation genetic aneuploidy screening in IVF Hum. Reprod. Update, January 1, 2007; 13(1): 15 - 25. [Abstract] [Full Text] [PDF]
|
|